feat(runs): add log search with backend LIKE filter and pagination

- add Search pill component with lucide icon and focus highlight
- wire debounced search input to GET /run/:id?q= backend filter
- backend filters run logs with LIKE %q% via TypeORM
- add sectionHeadingRow layout for heading + search alignment
- add i18n keys: runs.step_title, logs_search_placeholder

client/src/i18n/locales/en.json

@@ -198,7 +198,9 @@
     "field_created": "Started",
     "field_updated": "Updated",
     "steps_heading": "Step runs",
+    "step_title": "Title",
     "logs_heading": "Logs",
+    "logs_search_placeholder": "Filter logs…",
     "step_order": "#",
     "step_type": "Type",
     "step_session": "Session",